LPL VCCE Head

Stephen Weston · Apr 5, 2021

I have recently acquired an LPL 7451 ( I think it would be a Saunders in the US) which has both colour and the VCCE modules. Now my understanding with the VCCE head is the exposure time will remain constant no matter the grade selected. I tried this out on a quick test the other night using MG V. Using the Durst easel that opens up into quarters on 10x8 sheet ( can't think of the official name) I printed at grade 0, 2, 3.5 and 5. the lower grades were fine but 5 needed twice the exposure. I know this applies when using the Ilford filters but I wasn't expecting it with this head. So my question is - is this normal even with these type heads or am I missing something?

bripriuk · Apr 5, 2021

Yes, this is normal on an LPL enlarger, and I think most others as well.

Brian P

voceumana · Apr 5, 2021

And the concept of "constant exposure" is somewhat limited, as with different degrees of contrast we may prefer (artistically) a darker or lighter print--i.e., it gets you in the ball park but may need some tweaking.

MattKing · Apr 5, 2021

With the older MGIV you may have needed adjustments at the grade 4 level as well.
The thing to remember with any speed matching system is that they are keyed to one particular tone. That tone is usually a high mid-tone, close to light coloured Caucasian skin.
If you are basing your exposure decisions on lighter or darker subjects, the speed matching won't work exactly. It does get you closer though.

Nicholas Lindan · Apr 5, 2021

It all depends on the shade of grey you want to hold 'constant' between grade changes.

The Ilford papers & filters:

MGIV RC & FB hold 0.55OD constant for grades #00-3.5, and hold 0.95OD constant for grades #4-5;
MGIV WT holds 0.90OD constant for grades #00-3.5 while grades #4-5 don't have any place where the grey tone holds constant.

0.55OD is halfway between ZV (18%, 0.70OD) and ZVI (skin, 0.47OD).
0.90OD is around ZIV (light shadows, 1.00OD).

Reference the HD graphs provided at http://www.darkroomautomation.com/support/index.htm

Stephen Weston · Apr 5, 2021

Thanks all for coming back. I figured this was the case but having previously used under the lens filters prior to obtaining this head wasn't to sure.

Danner · Apr 8, 2021

Nicholas Lindan said:
It all depends on the shade of grey you want to hold 'constant' between grade changes.

The Ilford papers & filters:

MGIV RC & FB hold 0.55OD constant for grades #00-3.5, and hold 0.95OD constant for grades #4-5;

MGIV WT holds 0.90OD constant for grades #00-3.5 while grades #4-5 don't have any place where the grey tone holds constant.

0.55OD is halfway between ZV (18%, 0.70OD) and ZVI (skin, 0.47OD).
0.90OD is around ZIV (light shadows, 1.00OD).

Reference the HD graphs provided at http://www.darkroomautomation.com/support/index.htm

You must be a wizard

Nicholas Lindan · Apr 9, 2021

Danner said:
You must be a wizard

Just call me "Rincewind"

LPL VCCE Head

Stephen Weston

bripriuk

voceumana

MattKing

Moderator

Nicholas Lindan

Advertiser

Stephen Weston

Danner

Nicholas Lindan

Advertiser

LPL VCCE Head

Moderator

Advertiser

Advertiser

Privacy & Transparency

Privacy & Transparency